Gene transcription in eykaryotes will be studied at the nucleoprotein level of organization. Two interrelated lines of investigation will be pursued. The metabolically-stable RNA molecules that we have found in purified HeLa cell chromatin will be characterized further with specific reference to their possible role in gene activation. We are especially interested in whether this chromatin-bound RNA is produced from a hnRNA precursor. We will also continue our investigation into the structure and function of ribonucleoprotein particles that contain heterogeneous nuclear RNA and messenger RNA in a variety of mammalian cells and in the cellular slime mold, Dictyostelium. Particular attention will be focused on the possible roles of hnRNP-associated proteins in the metabolic processing of hnRNA. Throughout this program, attempts will be made wherever possible to integrate data from these two separate lines of investigation into a unifying scheme of gene regulation in higher cells, particularly with regard to the role of heterogeneous nuclear RNA in such control. BIBLIOGRAPHIC REFERENCES: Firtel, R.A. and Pederson, T. (1975) Ribonucleoprotein Particles Containing Heterogeneous Nuclear RNA in the Cellular Slime Mold, Dictyostelium discoideum. Proc. Natl. Acad. Sci. U.S.A. 72:301-305. Kish, V.M. and Pederson, T. (1975) Ribonucleoprotein Organization of Polyadenylate Sequences in HeLa Cell Heterogeneous Nuclear RNA. Journal of Molecular Biology 95:227-238.